Field of the Invention
The present invention relates to the field of fuel tank construction for automotive engines.
Description of the Related Art
As is well known, automobiles are equipped with fuel tanks for storing fuel to be fed to the engines. Long trips are now popular with the spread of express highways, so that large-capacity automotive fuel tanks are required to prevent running out of fuel which may occur during extensive touring.
On the other hand, there is a demand for reduction in size of the automobile as a whole, so that the large-sized fuel tank may cause interference with other parts of the frame. Further, it is quite difficult to give the first priority to the fuel tank in designing an automobile. In consequence, automotive fuel tanks usually cannot have plane side surfaces, and the bottoms are usually convexed and concaved largely in order to permit mounting of other automotive parts. Thus, in many cases, fuel tanks have two or more deep wells or compartments.
For instance, a fuel tank 1 shown in FIG. 1 has two wells 2, 3 which are separated from each other by a recess 4 along the tank bottom, the recess 4 being formed in order to provide a space for the automotive frame or other parts. Singular inlet tube 5, main tube 6 and return tube 7 are arranged in a manner to simplify the construction as much as possible. In order to enable the fuel to be supplied to the engine through a single main tube 6 after the fuel level 8 has come down below the level of the top of the recess 4, the compartments 2 and 3 are communicated with each other through an underhanging tube 9 which serves as a communication tube.
In the fuel tank 1, however, since two compartments 2, 3 are communicated with each other through the underhanging tube 9, the tube 9 tends to interfere with other constituent parts of the vehicle such as the frame or other equipment, thus making the provision of two compartments separated by the recess 4 meaningless. In consequence, the degree of freedom for the installation of the fuel tank 1 is undesirably reduced.
It would be possible to arrange the tube 9 such that it extends below the frame and other equipment. Such an arrangement, however, increases the protective maintenance requirements.
In order to overcome this problem, Japanese Utility Model Laid-Open No. 53123/1984 proposes an arrangement in which an overhanging, i.e., upwardly convexed, siphon is provided between two compartments, with a float attached to the inlet of the siphon. This arrangement, however, necessitates valves for respective openings of the siphon, so that the construction is complicated and protective maintenance work is rendered troublesome, resulting in increased cost of production.